Well, a little surprised. I didn't expect this. Anyway I am grateful to you for your saying this.
Is it true that inviting friends for a lunch or dinner is still a way for people to show their thanks? Also crowning a condition such as once I ... on the invitation to imply that it would not happen?
Earning a big amount of money is too ambiguous here and now days it is not impossible to get an income of 100 thousand dollars a year. If I were you, I would say once I win a lottery of ten million dollars :-)